Method of obtaining sweet doctor test



E. B. MILLER METHOD OF OBTAINING SWEET DOCTOR TEST Nov. 1, 1927.

' Filed Nov. 0, 1924 I Patented Nev. 1, 19 27.

UNITED STATES ERNEST B. MILLER, OF BALTIMORE, @IAEYLAND, ASSIGNOR TO THE SILI CA. GEL COR- POBATION, OF'BALTIMORE, MARYLAND, A CORPORATION OF MARYLAND.

{METHOD OF OBTAINING SWEET DOCTOR TEST.

Application filed November- 10, 1924. Serial No. 748,016.

The present invention relates to a method of treating light petroleum distillates such as gasoline, kerosene, etc.

' At the present time, it is customer to include in the specification of a re ed petroleum product such as gasoline or kerosene the requirement that the product be sweet to the doctor test (sodium plumbite).

After a petroleum product has been .refined by treatment with a porous adsorbent material like silica gel, in some cases a p0s-- itive doctor test is obtained, that is to say,

there is a visible reaction when the product is mixed with some of the doctor solution. It is the object of the present invention to provide an improved process whereby the product obtained by refining with a porous body like silica gel is sweet to the doctor test, that is to say, there is no visible re- 2 action when the product is mixed with the doctor solution.

Referring to the drawings: Fi 1 is a plan view of a device for treating 'ght petroleum distillates in accordance with the present invention;

Fig. 2 is a section taken substantially on the line 22 of Figure 1;

Fig. 3 is a vertical sectional elevation through another form of apparatus for treating the distillates in accordance with this invention.

The so-called doctor test consists in shaking about two volumes of the product being treated with one volume of the doctor solution. The doctor solution is made from sodium hydroxide and lithar e (Pbo) in the proportions of about 125 amsof the sodium hydroxide in one liter of distilled water and 60 grams of the litharge. If

there is any visible reaction betweenthe.

product and the solution, the test, is said to be sour or positive. If there is no visible reaction, the test is said to be sweet or negative. I This test is supposed to indicate whether or not any substantial amounts of free'acid or certain sulphur compounds are present. A peculiar phenomenon relative to petroleum products refined by a porous material like si ica gel is that although more sulphur is removed than by chemical methods of refining, the refined product in some cases is not sweet or negative when subjected to the doctor test. According to the present invention, it is section of which is substantially rectangular found, if the refined product is subjected to actinic rays, for example, sunlight or rays from a mercury vapor lamp, a sweet prodpctc is obtained when subjected to the doctor In refining light petroleum distillates with a 1ptrlirous body like silica gel, the oil being re ed is brought in contact with the porous adsorbent, whereupon substances in solution like sulphur compounds are adsorbed in the pores of the adsorbent. Thereafter the adsorbent is revivified or activated so that it may again be used to treat more oil.

According to the present invention, the refined product discharged from the refining apparatus is exposed to actinic rays. The length of time of the exposure depends on the condition of the refined product, the intensity and-wave length of the rays, and the thickness of the layer of oil being treated. In view of these four variables, 1t is diflicult to give a definite statement as to the .for too long, a time the oil is likely to be discolored and this naturally, is to be avoided.

To carry out this treatment, the conduit through which the refined oil discharged from the refining lant is flowing may be enlarged into a wi e thin passage, the cross in outline and the height of which is very smallso that the oil is flattened out into a wide thin layer. Suitable actinic -rays are directed either on the top or bottom, or both,

f this flattened passage, the walls of the passageway zgbein transparent. I

A device of this kind is shown in Figures 1 and 2. y lhe conduit A is connected with aiiattened casing B which may be of the form 'shown in. i res 1- and 2 and has transparenttop an bottom walls. Sources G of actinic rays ma be disposed either above or below the casing B, or both above and below as shown.

The light petroleum distillate discharged 11o from the silica gel refining plant flows through the condult A and casing B and is discharged at D. The rate of flow through the casing- B may be controlled by a valve E in the conduit A so that the distillate will be subjected 'to the actinic rays for the- I proper length of'time to render the distillate sweet to the doctor test.

Another form of device for subjecting the distillates to actinic rays is illustrated diarays an'd'the inner ends of the baflle plates.

Another series oi baflie plates K alternate with the bafile plates .J and are disposed so there is no passage between their inner ends and the source of rays but their outer ends are spaced from the casing thereby forming narrow passageways at their outer ends. The distillate that has' been refined by the silica gel process enters through the conduit L and then is divided by one of the bafile lates K, a'portion going to the right there ore and the remainder to the left. The portion that flews' to the right. because of the bafle plates K'and J, is caused to move inwardlytoward the source of rays and then around the inner edge of bafile plate J, then outwardly and around the outer end of bafile plate K, and then inwardly, and around the .mner end of the next baflle plate J and finally dischar d'through the outlet M. The portion 0 the distillate that flows to the left moves through; asimilar path. In this way the distillate is more or less agitated and. given a very thorough treatment by the rays. The rate of flow through the casing may be controlled by a'valve N.

Having thus described my invention, whatis claimed as new and desired to be secured by United States Letters Patent is:

1. The method of rendering sour light petroleum distillates, which have been re-L fined by treatment with a porous adsorbing material, sweet to the doctor test, consisting in exposing the product thus refined to actimc rays.

2. The method of rendering sour light;

petroleum distillate's, which have been refined by treatment-with silica gel, sweet to the doctor test, consisting in exposing the product sthus refined to actinic re s.

3. The method of renderin a' sour light. to the doctor petroleum distillate 4 sweet test, which consists in refining such distillate by treatment with a porous" adsorbing material and thereafter exposing it to aetinic re 5. I

n testimony whereof I hereunto aflix my signature.

ERNEST B. MILLER. 

